A new discovery has upended the widely held view that all pulsars are orderly ticking clocks of the universe. A survey done at the Arecibo Observatory in Puerto Rico has fortuitously discovered two extremely strange pulsars that undergo a “cosmic vanishing act.” Sometimes they are there, and then for very long periods of time, they are not. Read More

M-class asteroids are a relatively rare type of asteroid in the main asteroid belt, located between the orbits of Mars and Jupiter. For many years, planetary scientists have thought that they were the remnants of small protoplanets that were shattered in the violent early days of the solar system, leaving only an exposed metal core behind. Unfortunately, determining whether an asteroid is mostly metallic is very difficult with traditional optical telescopes. For the past decade, we have used the Arecibo Planetary Radar to probe these objects, for only a radar telescope can give an unambiguous indication of a metallic composition. Read More

Though not visible to the naked eye or even with binoculars, the green-tailed Comet 45P/Honda-Mrkos-Pajdusakova (HMP) did not escape the gaze of the world-renowned Arecibo Observatory. Scientists from the University of Arizona’s Lunar and Planetary Laboratory (LPL) and the Universities Space Research Association (USRA) at Arecibo Observatory have been studying the comet with radar to better understand its solid nucleus and the dusty coma that surrounds it.